Most recreational and utility trailers, are equipped with hydraulic brakes which are generally actuated responsive to sensed approach of the towed and towing vehicles toward each other, such as deceleration or backing up of the towing vehicle relative to the towed vehicle. Such brakes are known generally as surge brakes. During deceleration of the towing vehicle, such as in slowing speed or in coming to a full stop, it is desirable to have the trailer vehicle brakes be applied together with those of the towing vehicle. However, when these vehicles approach each other due to backing up of the towing vehicle, simultaneous application of the trailer brakes will impede maneuverability.
Accordingly, it is an object of the present invention to provide a braking system in which the power generation system for the trailer brakes, that is the trailer hydraulic pump, is enabled responsive to an electrical signal from the towing vehicle, such as application of the towing vehicle brake pedal.
Braking systems are currently available in which both towing and trailer vehicle brakes are controlled responsive to a signal from the towing vehicle. Thus, U.S. Pat. No. 4,402,553, Hipps, describes hydraulic brakes for a towed vehicle, in which an electro-magnet variable valve in the towed vehicle provides the responsive braking pressure by employing an electric current signal generated by a pedal force sensor in the towing vehicle to create an electromagnetic force balanced against the hydraulic pressure present in the towed vehicle brakelines. The towed vehicle is slowed without any hydraulic connection between the two vehicles. The device, however, does not sense deceleration of the towing vehicle in combination with the application of brakes in the towing vehicle.
U.S. Pat. No. 3,951,464, Donahue, relates to a truck-trailer brake system utilizing a hydraulic trailer brake system in which the hydraulic pump is driven by an electric motor carried by the trailer, but the pump is controlled from the truck, so that only simple electrical connections between the truck and the trailer are required. However, the Donahue system does not include an additional sensor responsive to truck deceleration as does the present inventive system.